When it comes to Bond cars, this vehicle is almost as iconic as the Aston Martin DB5.

September's auction of the Lotus Esprit submarine car represents once-in-a-lifetime opportunity to own one of most famous film cars of all time.

No other Bond car has ever done anything as outrageous as transform itself into a submarine.

The Lotus sub car, nicknamed "Wet Nellie", was used to incredible effect in the James Bond film, The Spy Who Loved Me, starring Roger Moore.

It frequently tops the polls when generations of movie fans are asked to vote on their favourite film cars of all time.

The vehicle being offered by RM Auctions on September 8-9 in London, is the one and only fully functioning car especially designed and built for the famous underwater sequence seen on screen in the 1977 film.

It was developed from one of six Esprit body shells used in the making of the film.

As the only car to be built into a fully operational, self-propelled ''submarine'', by Perry Oceanographic, based in Riviera Beach, Florida, it is the vehicle which claimed the most screen time in the film.

The driver of the car was Don Griffin, a retired US Navy Seal and test pilot for Perry, who operated the vehicle utilising its motorised propellers while manoeuvring with levered steering mechanisms. At the time, the car was said to have cost over US$100,000 to create (which is over a half million dollars today).

After filming in the Bahamas, the vehicle was shipped to Long Island, New York, where it was kept in an unassuming storage unit on a 10 year rental, paid in advance. In 1989, the then rent delinquent unit was put up ''blind'' for public auction. A modest winning bid from an area couple brought surprise and wonder when the blankets were removed to reveal the iconic 007 ''submarine'' car. After positive authentication, the Lotus was shown occasionally – including a stint at the Petersen Automotive Museum – but mostly kept closely under wraps, until now.

RM Auctions sold "the most famous car in the world", the Aston Martin DB5 used by Sean Connery in the enormously popular Goldfinger and Thunderball movies, for an incredible £2.9 million (NZ$5.6m) during its 2010 London sale.